Mobile device for filtering liquid under pressure

ABSTRACT

A device for filtering liquid, including a first reservoir for collecting filtered liquid, a second reservoir for liquid to be filtered, the second reservoir contained at least partially in the first reservoir, the walls of said second reservoir having at least a filtering opening allowing transfer of liquid between the first and second reservoirs, an injection opening having a filter blocking the filtering opening, and a flexible pressurization device to inject air into the second reservoir via the injection opening. The pressurization device is located completely outside the second reservoir, and has a volume that is variable between two positions: a deployed position, in which the volume of the pressurization device is maximal, and a folded position, in which the volume of the pressurization device is minimal.

TECHNICAL FIELD OF THE INVENTION

The field of the invention is that of systems for filtering liquid underpressure, intended in particular to be used for purifying water bypassage under pressure through a filter of the ceramic type.

In particular, the invention relates to a compact self-containedfiltration device suitable for being easily transported daily, whiletaking into account the maintenance of good hygiene and optimisation ofthe purification process.

TECHNOLOGICAL BACKGROUND

Essential to life, water is a resource of prime importance. Despite thevital requirement that it constitutes for every individual, water isalso a significant carrier of illnesses, and problems related to accessfor everyone to good-quality water remains a major challenge to be dealtwith at this start of the 21st century.

On an individual scale, various means are used daily to purify water.Thus US 2010/0237002 describes a personal filtration device that can befitted sealingly on the spout of a tap. The water expelled underpressure from the pipe is thus filtered by passing through a filterbefore being poured into a bottle. Use of this device therefore requiresthe user to be in the immediate vicinity of a specific water supplysource, in this case a tap, which limits its mobility. In addition, thedevice does not comprise a means for storing filtered water. Thefiltered water is therefore intended to be consumed immediately orstored in an external receptacle, without preventing potentialcontamination of the water during transfer into it.

Other more complex methods make it possible to overcome thesedifficulties.

Thus US 2010/0200489 describes a pressurised water filtering carafecomprising two water reservoirs. The first reservoir is fitted into thesecond so that the transfer of water from one reservoir to the other canbe effected only by passing through a filter, itself consisting of asuperimposition of filtering layers. The carafe is made airtight by thefitting of a lid on which a pressurisation device is fitted in the formof a piston. By activating the piston, the user injects air into thecarafe, which accelerates the process of filtration of the watercontained in the first reservoir. The major drawbacks of this carafe arerelated to the introduction of the piston into the first receptacle,which increases the risks of contamination of the piston by pathogens,as well as the rigid nature and the complexity of the piston, making thelatter more difficult to produce but also more fragile.

Other methods comprising a pressurisation device arranged outside thereceptacle collecting water to be filtered partly overcome thesedifficulties. However, the means developed have the common feature ofbeing detrimental to the overall compactness of the filtration device,which constitutes a prohibitive obstacle with regard to the industrialapplications targeted by the invention.

OBJECTIVES OF THE INVENTION

The invention aims to overcome at least some of the drawbacks present inthe prior art.

In particular, the invention aims to provide a device for filteringliquid under pressure that is not complex and combines goodself-containment of use, robustness to external impacts and maintenanceof good hygiene, while keeping maximum compactness in order to be ableto be stored or transported easily.

The invention also aims to provide, at least in one embodiment, afiltration device that can easily be assembled and disassembled, inorder to facilitate the transport and cleaning of the device and thecharging of it with water to be filtered.

The invention also aims to provide, in at least one embodiment, afiltration device inside which a filter can be fitted in the form of acartridge or allowing the implementation of an ultrafiltration method.

The invention also aims to provide, in at least one embodiment, afiltration device enabling the user, after loading of the water to befiltered, to initiate the filtration method when he so wishes.

DISCLOSURE OF THE INVENTION

These objectives, as well as others that will emerge more clearlyhereinafter, are achieved by means of a liquid-filtration devicecomprising:

-   -   a first receptacle intended to collect the filtered liquid,    -   a second receptacle intended to contain the liquid to be        filtered, said second receptacle being contained at least partly        in said first receptacle, the walls of said second receptacle        having at least two openings: a filtration opening, suitable for        transferring liquid between said first and said second        reservoir, and an injection opening,    -   a filter closing off said filtration opening,    -   a pressurisation device for injecting air into said second        receptacle through said injection opening, characterised in that        said pressurisation device is a flexible device, completely        located outside said second receptacle, and occupying a variable        volume between two positions:    -   a deployed position in which the volume occupied by the        pressurisation device is at a maximum,    -   a folded position in which the volume occupied by the        pressurisation device is at a minimum, and in that said folded        position is, in the absence of any action by a user, a stable        position.

Throughout the text, the term “flexible” describes the ability of anobject to fold without breaking.

A filtration device according to the invention confers on the user goodself-containment of use, comprising within its structure means forstoring and filtering the targeted liquid. Thus the first and secondreservoirs respectively contain the filtered liquid and the liquid to befiltered. The user is therefore not subjected to the need to be situatedclose to a liquid-supply source in order to operate the device, nor touse a third collecting receptacle to collect the filtered liquid. Thepresence of a pressurisation means for its part accelerates thefiltration method. This pressurisation means being located outside thesecond receptacle, the introduction of foreign bodies inside the secondreceptacle or the pressurisation device, and therefore the risks ofcontamination that are related thereto, are thus limited. This isbecause, in the contrary hypothesis, putting the pressurisation means incontact with the liquid to be filtered contained in the secondreceptacle would increase the probability of a mutual exchange ofpathogens. A first loading of liquid to be filtered could for exampleinitially contaminate the pressurisation device before the latter in itsturn contaminates a second load of liquid to be filtered, thereby makingthe action of the filter more complex. The location of thepressurisation device outside the second receptacle therefore limitsthese detrimental effects as well as the constraints related to thecleaning of the pressurisation device. According to the invention, thepressurisation device is, in the absence of action by the user, in astable position in which the space occupied by pressurisation device isat a minimum. The filtration device therefore has, when it is at rest,maximum compactness, which facilitates its placing in a small space forpurposes of storage or transport. The compactness of the pressurisationdevice and its flexible character are also indications of reinforcementof the whole of the structure, enabling the pressurisation device tobetter withstand the external mechanical impacts that may be caused. Thefiltration device is therefore more robust.

According to a particular feature, the filtration device comprises aseal, fitted on the second receptacle so as to close off the injectionopening, and allowing only a unidirectional passage of air, from theoutside to the inside of said second receptacle.

Thus the seal does not enable air or liquid to be transferred from thesecond receptacle to the pressurisation device, in particular betweenthe various phases of injection of air from the pressurisation deviceinto the second receptacle. The pressure equilibrium inside the secondreceptacle is achieved by transferring liquid from the second receptacleto the first, by means of the filter. The action of the pressurisationdevice on the filtration process is therefore reinforced by thearrangement of the seal. The seal also limits contamination of thepressurisation device by the second receptacle, which has the technicaleffect of improving the hygiene of the filtration device, reducing thecosts of cleaning the pressurisation device and increasing the servicelife of the latter.

According to this particular feature, the seal is fitted removably onthe second receptacle.

Thus the seal can be removed from the second receptacle by the user soas to allow the loading of liquid to be filtered from the secondreceptacle, the cleaning of the device or the replacement of a defectivepart.

According to a particular feature, the filtration device comprises acover protecting the pressurisation device.

Thus the resistance of the pressurisation device to external mechanicalimpacts is increased. The filtration device is therefore more robust.

According to this particular filter, the filtration device comprisesmeans for the removable fixing of the protective cover on the secondreceptacle.

Thus, when the protective cover is arranged with the second receptacle,it enables the filtration device to have an additional sealing meanswhile increasing the robustness of the filtration device.

According to a particular feature, the filtration device comprises meansfor the removable fixing of said pressurisation device on the secondreceptacle.

Thus, when the pressurisation device is arranged on the secondreceptacle, it enables the filtration device to have an additionalsealing means while reinforcing the robustness of the filtration device.In addition, the removable character of this fixing means enables a userto be able to remove these various parts for the purpose of facilitatingtransport thereof, maintenance thereof or the charging of the secondreceptacle with liquid.

According to a particular feature, the filter is at least partly madefrom ceramic and has a hollow tubular shape, closed on a first end, asecond end closing off said filtration opening.

Filtration by ceramic filter is in general extremely fine, around 0.2microns, because of the miniscule pores that constitute itsmicrostructure. The use of a ceramic filter thus makes it possible tostop microorganisms that are hazardous for health, such as viruses orbacteria. It can also be envisaged combining ceramic filtration with atraditional chemical treatment, which eliminates additional chemicalcomponents that may be dissolved in the filtered liquid. Theconformation of the filter “in a cartridge” for its part maximises thefiltering surface in contact with the liquid to be filtered, for thepurpose of increasing the efficiency of the filter. It may also beenvisaged using a filter that is impermeable to air, so that only liquidfluids can pass through. Thus the filtration process can remaineffective in the case of partial immersion of the filter in the liquidto be filtered.

According to a particular feature, the size of the pores of at least onemembrane of said filter is between 0.1 and 0.001 microns.

When the size of the pores of a ceramic filter is between 0.1 and 0.001microns, ultrafiltration is spoken of. Unlike a conventional filtration,which limits the passage of large molecules by retaining them in itslattice of pores, ultrafiltration blocks the impurities at the entry tothe lattice, allowing only molecules of very small size to pass. Theseimpurities can then be eliminated by the dynamic effect of the fluid inlocal contact with the filter or following simple cleaning. Consequentlythe efficiency of the filter and its service life are considerablyincreased, the risks of bacterial contamination inside the filter arereduced and cleaning is made easier. On the other hand, because of thereduction in the size of the pores, the functioning of this methodrequires the existence of a pressure differential between the walls ofthe filter, which justifies the use of a pressurisation means in thecontext of the invention.

According to a particular feature, the filtration device comprises anopening for discharging the filtered liquid, closed off in the foldedposition.

Thus the closure of the discharge opening when the filtration device isat rest ensures the fluidtightness of the first receptacle and limitsthe risks of bacterial contamination of the filtered water contained insaid receptacle.

According to a particular feature, the second receptacle is divided intotwo compartments by a sealed partition that comprises in its upper partan opening able to allow decanting of said liquid from one of saidcompartments to the other, by tilting said filtration device in alateral direction.

In the case of a first compartment arranged so as to collect the liquidloaded into the filtration device and a second compartment comprisingthe filtration opening and the associated filter, the user has theability, through the decanting of the liquid from the first to thesecond compartment, to initiate the filtration process according to hisconvenience and, if necessary, for a long time after the water has beenloaded into the filtration device. The risks of bacterial proliferationthat may result from prolonged stagnation of the filtered water in thefirst reservoir are thus limited.

LIST OF FIGURES

Other features, aims and advantages of the invention will emerge from areading of the following description that presents, by way ofnon-limitative example, an embodiment of the invention, with referenceto the accompanying drawings; in these drawings:

FIG. 1 is a telescoped view in perspective of the filtration device,

FIG. 2 is a schematic view of the ceramic filter,

FIG. 3 is a schematic view of the filtration device in the foldedposition, after loading of the liquid,

FIG. 4 is a schematic view of the filtration device in the deployedposition,

FIG. 5 is a schematic view of the filtration device in the foldedposition, after filtration of the liquid,

FIG. 6 a is a schematic view of the first reservoir in the position ofloading of the first compartment with liquid,

FIG. 6 b is a schematic view of the first reservoir in the position ofdecanting liquid from the first compartment to the second,

FIG. 6 c is a schematic view of the first reservoir in the position ofinitiation of the filtration process.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

In the figures, the scales and proportions are not strictly compliedwith, for purposes of illustration and clarity. Throughout the detaileddescription that follows with reference to the figures, unless indicatedto the contrary, each element of the filtration device is described asarranged when the base of the first receptacle is mounted horizontally.This arrangement is in particular shown in FIGS. 1, 3, 4, 5, 6 a and 6c.

In FIGS. 1, 3, 4 and 5, the filtration device 1 comprises a firstreceptacle 2, having the form of the lower portion of a bottle, providedon its lower part with a base 2 a enabling it to be placed in a stablemanner on a flat surface, and, on its upper part, with an open crosssection S1, oriented on a substantially horizontal plane. With theobjective of facilitating handling thereof by a user, the firstreceptacle 2 may comprise, on at least one of its lateral walls, ahandle, with non-slip surfaces, or an ergonomic design allowing easygripping of the first receptacle 2 by hand. A second receptacle 3 iscomposed of a reservoir 3 a, with a volume at least less than half thatof the first receptacle 2, having, on one of its walls, an openingreferred to as the filtration opening S2 and, on its upper part, an opencross section S3, oriented on a substantially horizontal plane, andhaving on its external circumference a collar 3 b. This collar 3 b issized so as to cover the whole of the circumference of the open crosssection S1 when the reservoir 3 a is introduced into the firstreceptacle 2. The first receptacle 2 is then hermetically closed by thesecond receptacle 3 with the exception of the filtration opening S2 anda discharge opening S4 provided in the collar 3 b. A seal 4 is arrangedremovably, by screwing, on the upper part of the second receptacle 3, soas to close off its open cross section S3. This seal 4 comprises at itscentre a valve 4 a that allows the passage of air only from the outsideto the inside of the second receptacle 3. A cap 5 is fitted removably onthe seal 4 so as to be able to protect the latter from any externalmechanical impacts. This cap 5 has at its centre an opening S5 enablingair to pass.

The filtration device 1 also comprises a pressurisation device 6comprising a first seal referred to as the injection seal 6 a and asecond seal referred to as the loading seal 6 b, both placed insubstantially horizontal planes and separated from each other by aflexible tubular-shaped element 6 c, extensible mainly in a verticaldirection and delimiting, with the injection seal 6 a and the loadingseal 6 b, a hermetic cavity 6 d of variable volume V. The loading seal 6b and the injection seal 6 a each comprise at their centre a valveallowing only a unidirectional passage of air and allowing respectivelythe entry and exit of air to and from the cavity 6 d. A compressingspring 6 e connecting the respective centres of the injection seal 6 aand the loading seal 6 b tends to oppose the moving away of the twoseals. A protective cover 7, concave in shape and having an open crosssection substantially identical to S1, is fixed, with its cavityoriented downwards, on the external face of the loading seal 6 b. Theprotective cover 7 has an opening S6, allowing a passage of air, thecentre of which is included in the axis X defined by the respectivecentres of the injection seal 6 a and the loading seal 6 b. The distanceD separating the injection seal 6 a from the loading seal 6 b varies,according to the movement of the latter, along the axis X, between twopositions: a so-called folded position, characterised in that thedistance D reaches its minimum value, and a so-called deployed position,characterised in that the distance D reaches its maximum value. Theextreme values taken by the distance D are determined by the capacity ofthe tubular-shaped flexible element 6 c to extend and contract along theaxis X. The volume V being proportional to the distance D, the volume Vtherefore reaches its minimum and maximum values in the positionsrespectively folded and deployed. The movement of the loading seal 6 bwith respect to the injection seal 6 a along the axis X is governed bythe work of the extension force exerted by the user and the return forceexerted by the compressing spring 6 e. The protective cover 7 comprises,on its external face, grips 7 a enabling the fingers of the user to havea better grip. The pressurisation device 6, in the absence of the actionof a user, tends to return to the folded position under the effect ofthe compressing spring 6 e. The external face of the injection seal 6 ais arranged by a fixing by removable screwing on the collar 3 b, so thatthe respective centres of the open sections S3 and S5 and of the valve 4a are aligned along the axis X. The protective cover 7 and the collar 3b are, when the pressurisation device 6 is in the folded position, fixedremovably by the use of opposite polarisation magnets.

In FIG. 2, the ceramic filter 8 has a hollow tubular form, closed on afirst end 8 a, a second end 8 b closing off said filtration opening S2.The filter 8 is fixed removably to the bottom of the second receptacle3, by means of screwing, so that the whole of the filter 8 is containedin the second receptacle 3. The filter 8 is intended for the filtrationof water, with a mean capacity of 5000 litres, according to the qualityof the water to be filtered and the frequency of cleaning of the filter8.

In the following description of the filtration process, the targetedliquid is water. However, according to other embodiments, the water isreplaced by another liquid and the filter is adapted accordingly.

In the text, the removable fixing means described are screwing systems.However, according to other embodiments, screwing systems are replacedby push-in systems or clips. The latter have in particular the advantageof adapting to non-circular shapes. It is the elasticity of the materialthat then ensures the closure and sealing.

The various operating phases of the filtration device 1 are describedbelow in their chronological order of use.

During the phase of loading with water, the pressurisation device 6, thecap 5 and the seal 4 are disengaged so as to free up access to thereservoir 3 a of the second receptacle 3. The user then fills thereservoir 3 a with water. Once the filling is effected, the seal 4, thecap 5 and the pressurisation device 6 in the folded position arerearranged on the rest of the filtration device 1, as depicted by FIG.3.

During the phase of loading with air, the user produces a tension forceon the pressurisation device 6, via the grips 7 a, and tends to move theloading seal 6 b away from the injection seal 6 a by translation alongthe axis X. This work opposes that of the compressing spring 6 e. Thevolume V of the cavity 6 d increases proportionally to the distance D,giving rise to a pressure differential between the inside and outside ofthe cavity 6 d that in its turn causes the valve of the loading seal 6 bto open and air to enter inside the cavity 6 d. Once the pressurisationdevice 6 is in the deployed position, as depicted by FIG. 4, thepressure differential decreases, causing the closure of the valve of theloading seal 6 b.

During the filtration phase, the user produces a compression force onthe pressurisation device 6 and tends to move the loading seal 6 bcloser to the injection seal 6 a by translation along the axis X. Thiswork is added to that of the compressing spring 6 e. The volume V of thecavity 6 d decreases proportionally to the distance D, causing apressure differential between the inside and outside of the cavity 6 dthat in its turn causes the opening of the valve of the injection seal 6a and of the valve 4 a, and the transfer of air from the cavity 6 a tothe reservoir 3 a of the second receptacle 3. The addition of air in thesecond receptacle 3 causes a pressure differential between the firstreceptacle 2 and the second receptacle 3, which causes a transfer ofwater, from the second receptacle 3 to the first receptacle 2, throughthe filter 8. Once the pressurisation device 6 is in the foldedposition, the pressure differential decreases, causing the closure ofthe valve of the injection seal 6 a. The transfer of water from thesecond receptacle 3 to the first receptacle 2 continues until thepressure differential between the two receptacles reaches a limit value,depending on the characteristics of the filter 8, marking the stoppageof the filtration process. At the end of the injection phase, asdepicted by FIG. 5, the pressurisation device 6 is in the foldedposition, closing the discharge opening S4.

It is then for the user to empty the first receptacle 2 by inclining thefiltration device and extending the pressurisation device 6 so as toleave clear the discharge opening S4 and thus enable the filtered liquidto be discharged from the first receptacle 2.

According to another embodiment and as depicted by FIGS. 6 a, 6 b and 6c, the second receptacle 2 is divided into two compartments by a sealedpartition 9 that comprises an opening S5 in its upper part. The firstcompartment 9 a is intended to collect the water loaded into thefiltration device by the user. The second compartment 9 b has thefiltration opening S2 around which the filter 8 is fixed. During theloading phase and as depicted by FIG. 6 a, the water is introduced intothe compartment 6 a by the user. During the decanting phase and asdepicted by FIG. 6 b, the filtration device is inclined by the user soas to enable the water initially contained in the first compartment 9 ato be transferred into the second compartment 9 b. During the phase ofinitiation of the filtration process and as depicted by FIG. 6 c, thewater transferred into the compartment 6 c is in a position to befiltered. The various operating phases of the filtration device 1 canthen be implemented as described above.

Various types of material make up the filtration device 1. Thus theseals 4, 6 a, 6 b and the extensible tubular-shaped tube 6 d are madefrom rubber, because of its impermeability and its good elasticity. Theother parts constituting the filtration device 1, apart from the filter,are made from plastics material, because of the lightness, the lowproduction costs, the low chemical reactivity and the good impactresistance of this material. However, according to another embodiment,the walls of the first receptacle 2 and of the protective cover 7 aremade from aluminium, because of the low thermal conduction of thismaterial. The device embodied according to this filtration mode thus hasbetter ability to preserve the coolness or warmth of the treated liquid.

1. Filtration device comprising: a first reservoir adapted to collectfiltered liquid, a second reservoir adapted to contain liquid to befiltered, said second reservoir being contained at least partly in saidfirst reservoir, walls of said second reservoir having at least twoopenings: a filtration opening, suitable for transferring liquid betweensaid first and said second reservoir, and an injection opening, a filterclosing off said filtration opening, a pressurization device forinjecting air into said second reservoir through said injection opening,such that said pressurization device is a flexible device, completelylocated outside said second reservoir, and occupying a variable volumebetween two positions: a deployed position in which the volume occupiedby the pressurization device is at a maximum, a folded position in whichthe volume occupied by the pressurization device is at a minimum, andwherein said folded position is, in the absence of any action by a user,a stable position.
 2. Filtration device according to claim 1, furthercomprising a seal fitted on the second reservoir so as to close theinjection opening and allow only a unidirectional passage of air from anoutside to an inside of said second reservoir.
 3. Filtration deviceaccording to claim 2, wherein said seal is removably fitted on thesecond reservoir.
 4. Filtration device according to claim 1, furthercomprising a protective cover for the pressurization device. 5.Filtration device according to claim 4, further comprising means for theremovable fixing of said protective cover on said second reservoir. 6.Filtration device according to claim 1, further comprising means for theremovable fixing of said pressurization device on said second reservoir.7. Filtration device according to claim 1, wherein said filter is atleast partly made from ceramic and has a hollow tubular shape, closed ona first end, and a second end adapted to close said filtration opening.8. Filtration device according to claim 1, wherein the size of the poresof at least one membrane of said filter is between 0.1 and 0.001microns.
 9. Filtration device according to claim 1, wherein saidfiltration device comprises an opening for discharging filtered liquid,which opening is closed in said folded position.
 10. Filtration deviceaccording to claim 1, wherein said second reservoir is divided into twocompartments by a sealed partition that comprises, in its upper part, anopening able to allow the decanting of said liquid from one of saidcompartments to the other, by tilting said filtration device in alateral direction.